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Alexi7 All-Star Author Ohio Posts:535 Points:13,930 Joined:Jul 2011	Message Posted: Jan 26, 2013 7:12:54 AM Ignore Alexi7 Report Abuse I've run this experiment a number of times(15W-50 Mobil 1 in the summer) and each time I lost 2-3 mpg. The worst case was my much-missed 1991 Accord EX coupe with a 5-speed. I went from 30-32 mpg down to 27-29 mpg and, I felt, some loss of power. Anyone else with a similar experience?

Alexi7

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Ohio

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Points:13,930
Joined:Jul 2011

Message Posted: Jan 26, 2013 7:12:54 AM

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I've run this experiment a number of times(15W-50 Mobil 1 in the summer) and each time I lost 2-3 mpg. The worst case was my much-missed 1991 Accord EX coupe with a 5-speed. I went from 30-32 mpg down to 27-29 mpg and, I felt, some loss of power. Anyone else with a similar experience?

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gvan Champion Author Chicago Posts:21,548 Points:2,838,240 Joined:Dec 2004	Message Posted: Jan 28, 2013 11:54:30 AM Ignore gvan Report Abuse "I use 5w-20" Ford recommends 5W-20 because it helps with their CAFE standards but I doubt the average owner will notice a difference in mpg.
WEPSMAN Champion Author South Dakota Posts:10,513 Points:2,024,600 Joined:Mar 2005	Message Posted: Jan 28, 2013 8:07:11 AM Ignore WEPSMAN Report Abuse I have not noticed. I usually run the same oil year round. Both my cars run 5W-30 and the diesel truck runs synthetic.
Saab93turbo Veteran Author Washington Posts:485 Points:85,235 Joined:Dec 2012	Message Posted: Jan 27, 2013 12:53:19 PM Ignore Saab93turbo Report Abuse Thinner oils, like 0W-20, tend to allow the car to get better gas mileage but too thin and it doesn't lubricate enough. In the old days, some sports cars used 20W-50 because the engine would get very hot. I would recommend following the car company's recommendation but if they have several choices, then use your own judgment. I think Mercedes Benz for some ooldercars recommends 10W-30, 10W-40
jbhubbell Rookie Author Alabama Posts:83 Points:33,755 Joined:Jan 2013	Message Posted: Jan 27, 2013 10:19:31 AM Ignore jbhubbell Report Abuse If you use a thicker oil than the engine is designed for you run the risk of starving the heads and thats where most of the heat and moving parts are. That is dumb.
Bridge2012 All-Star Author Kansas Posts:913 Points:271,290 Joined:Jan 2012	Message Posted: Jan 27, 2013 8:13:44 AM Ignore Bridge2012 Report Abuse I have never changed oil for a mpg test I seam to get one kind and stay with it to the end.
MertieMan Champion Author Lexington Posts:14,798 Points:2,897,560 Joined:May 2005	Message Posted: Jan 27, 2013 8:03:05 AM Ignore MertieMan Report Abuse I am currently using synthetic oil in my Corolla S and have experienced no problems such as this, but I always change oil when it is due.
twt Champion Author Virginia Beach Posts:8,748 Points:998,835 Joined:Mar 2005	Message Posted: Jan 27, 2013 6:35:53 AM Ignore twt Report Abuse I use the factory recommended viscosity, in both vehicles.
chipote Champion Author Washington Posts:1,274 Points:389,555 Joined:Nov 2010	Message Posted: Jan 27, 2013 4:28:58 AM Ignore chipote Report Abuse I use 5w-20
Alexi7 All-Star Author Ohio Posts:535 Points:13,930 Joined:Jul 2011	Message Posted: Jan 27, 2013 3:57:41 AM Ignore Alexi7 Report Abuse blueenvoy: Can't remember the last time I read an Owner's Manual. They're written for non-carpeople. I tried deciphering the oil change meter reset on my Pontiac G6. The tech at the dealership demonstrated an easier way and that's what I've stuck with.
Titanic1985 Champion Author South Carolina Posts:6,283 Points:359,520 Joined:Dec 2010	Message Posted: Jan 26, 2013 9:55:05 AM Ignore Titanic1985 Report Abuse Hi Alexi7. blueenvoy & OilerFan are correct in their recommendation to follow what the Owner's Manual recommends. You included many details (especially the model year of the vehicle), but did not state the mileage on the engine. 50W oil is extremely "heavy" for today's vehicles and typically used only in those with extremely high mileage and engine wear. The tolerances of modern engines now mandate a much lighter weight of oil, usually 5W-30 or 10W-30. You don't say, but I do hope you're not using 50W in Ohio's winter months? That is way too heavy! Answering your question, I only use the recommended 5W-30 Dexos 1 Mobil 1 oil in my 2012 Chevrolet Sonic, so I cannot give you a valid answer.
bluenvoy Champion Author Nashville Posts:14,985 Points:1,877,865 Joined:Oct 2005	Message Posted: Jan 26, 2013 9:12:29 AM Ignore bluenvoy Report Abuse Use what the manufacturer recommends for your engine. In the Owner's Manual.
the1roadhog Champion Author Atlanta Posts:9,913 Points:2,057,655 Joined:Jun 2007	Message Posted: Jan 26, 2013 7:39:30 AM Ignore the1roadhog Report Abuse Interesting. I've never seen that big a difference from my standard 5/20w.
OilerFan Champion Author Tulsa Posts:14,055 Points:2,448,025 Joined:Aug 2005	Message Posted: Jan 26, 2013 7:37:56 AM Ignore OilerFan Report Abuse I try to stick with what the manufacturer recommends.